The present invention relates to a recording medium such as an optical disc, an optical disc recording method and apparatus, and an optical disc reproducing method and apparatus.
A synchronization signal pattern in a frame unit of a Blu-ray Disc is disclosed in Table 6 of JP-A-2007-35263, and its paragraph [0060] describes the characteristics of the synchronization signal pattern, as “(1) (Tmax+1)−(T max+1), namely 9T-9T is given. Thus, since the pattern which breaks a maximum run is continued twice, the detection ability can be enhanced.” and “(2) 2T is given so that Tmax does not appear whatever a data modulation sequence is before 9T-9T. In other words, a short run is inserted so that no pattern of 8T-9T-9T appears in combination with a data part immediately preceding a synchronization signal to be inserted.”
JP-A-9-162857 describes, “The synchronous frame comprises a synchronization signal and a run length limited code which fills restrictions of a minimum run length and a maximum run length, and the synchronization signal includes the synchronization pattern constituted by a bit pattern of a run length that is longer than the maximum run length by only 3T and an addition bit pattern of a run length longer than the minimum run length which is arranged before and after the bit pattern.”